Safari crashes despite clean install.

Question

Safari is crashing, usually when I have been doing quite a bit of surfing and  hopping back and forth between multiple safari windows.  I initially had some sluggishness as well, which I thought could be related to any number of programs recently installed.  So I used time machine and reset my entire system back to a time right after a clean install of snow leopard and upgrade to mountain lion.  From there I ran all available updates.  The only thing I added was Office 2011 and its updates.  After a number of days, once again Safari crashed.  So I reset system back to the clean install and upgrade once again, but did not add any programs, including Office.  I browsed for a few days with no problems, until it crashed again, twice.
Just prior to the second crash, a little pop up said security updates had been installed.  I thought that was a little odd, since it usually doesn't just install them like that without my permission.    So I clicked on App Store updates to see if there was any more info, and a Safari 6.2.2 update was waiting for me, which I then installed.
from the All Messages window :
1st crash:
12/23/14 10:00:00.610 AM com.apple.launchd.peruser.501[158]: ([0x0-0x63063].com.apple.Safari[862]) Exited with code: 1
2nd crash:
12/23/14 5:55:06.034 PM com.apple.launchd.peruser.501[158]: ([0x0-0x23e23e].com.apple.Safari[3174]) Exited with code: 1
Mountain Lion and Safari 6.2.1  (and as of yesterday's update,  6.2.2).  I have a late 2009 model iMac.
3.06 GHz Intel Core 2 Duo
Memory  12 GB 1067 MHz DDR3
Graphics  NVIDIA GeForce 9400 256 MB
Software  OS X 10.8.5 (12F45)
I have added nothing other than the operating system, safari, iTunes, and their updates.  I haven't even installed Adobe Flash back on it yet.
Issues with sluggishness originally started in late October, and then started frequent crashing in late November.  So after a couple of day's of crashing, I used time machine to take me back to a clean install of Mountain Lion that I had saved.  Ran it for a while ok and then installed Office 2011 and updates and a bit later the crash occurred.  So I was thinking perhaps Office 2011 updates had been the cause.  So once again I reset back to the clean install with Time Machine, but this time I installed nothing else.  No Office.  Not even Adobe flash (just had to do without watching Facebook videos.  )  Same thing however.  After a few days, the crashes showed up again.
It may have something to do with my browsing, since I was researching and had about 6 safari windows running and bounced back and forth between them.
I can tell you I have no extensions other than Quick Time and iPhotoPhotocast that must have come with Apple updates and install.
I've had another crash since these.

Answer 1

Ok, well did the full shut down earlier.  Restarted later to use safari.  All went well.  Put into sleep mode while I left the computer for a couple of hours.  Came back and did just a little surfing, checking scores on ESPN and read some Facebook posts and it crashed while reading.
So here is the Etre:
Problem description:
safari crashed
EtreCheck version: 2.1.5 (108)
Report generated December 30, 2014 6:05:18 PM EST
Click the [Support] links for help with non-Apple products.
Click the [Details] links for more information about that line.
Click the [Adware] links for help removing adware.
Hardware Information: ℹ️
  iMac (21.5-inch, Late 2009) (Verified)
  iMac - model: iMac10,1
  1 3.06 GHz Intel Core 2 Duo CPU: 2-core
  12 GB RAM
  BANK 0/DIMM0
  4 GB DDR3 1067 MHz ok
  BANK 1/DIMM0
  4 GB DDR3 1067 MHz ok
  BANK 0/DIMM1
  2 GB DDR3 1067 MHz ok
  BANK 1/DIMM1
  2 GB DDR3 1067 MHz ok
  Bluetooth: Old - Handoff/Airdrop2 not supported
  Wireless:
Video Information: ℹ️
  NVIDIA GeForce 9400 - VRAM: 256 MB
  iMac 1920 x 1080
System Software: ℹ️
  OS X 10.8.5 (12F45) - Uptime: 7:5:20
Disk Information: ℹ️
  WDC WD5000AAKS-40V2B0 disk0 : (500.11 GB)
  disk0s1 (disk0s1) <not mounted> : 210 MB
  Macintosh HD (disk0s2) / : 499.25 GB (486.24 GB free)
  Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB
  HL-DT-ST DVDRW  GA11N 
USB Information: ℹ️
  Apple Inc. Built-in iSight
  Apple Internal Memory Card Reader
  Western Digital My Passport 0746 1 TB
  disk1s1 (disk1s1) <not mounted> : 32 KB
  disk1s2 (disk1s2) <not mounted> : 29 KB
  disk1s3 (disk1s3) <not mounted> : 29 KB
  disk1s4 (disk1s4) <not mounted> : 29 KB
  disk1s5 (disk1s5) <not mounted> : 29 KB
  disk1s6 (disk1s6) <not mounted> : 262 KB
  disk1s7 (disk1s7) <not mounted> : 262 KB
  disk1s8 (disk1s8) <not mounted> : 262 KB
  My Passport for Mac (disk1s10) /Volumes/My Passport for Mac : 1.00 TB (797.54 GB free)
  Apple Computer, Inc. IR Receiver
  Apple Inc. BRCM2046 Hub
  Apple Inc. Bluetooth USB Host Controller
Gatekeeper: ℹ️
  Mac App Store and identified developers
User Login Items: ℹ️
  iTunesHelper Application (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
Internet Plug-ins: ℹ️
  iPhotoPhotocast: Version: 7.0
  QuickTime Plugin: Version: 7.7.1
  JavaAppletPlugin: Version: 14.3.0 - SDK 10.8 Check version
3rd Party Preference Panes: ℹ️
  None
Time Machine: ℹ️
  Auto backup: YES
  Destinations:
  My Passport for Mac [Local]
  Total size: 1.00 TB
  Total number of backups: 135
  Oldest backup: 2012-08-20 00:04:31 +0000
  Last backup: 2014-12-30 22:28:22 +0000
  Size of backup disk: Excellent
  Backup size 1.00 TB > (Disk size 0 B X 3)
Top Processes by CPU: ℹ️
      3% WindowServer
      0% System Events
      0% fontd
      0% opendirectoryd
      0% mds
Top Processes by Memory: ℹ️
  103 MB mds
  103 MB Preview
  77 MB WindowServer
  26 MB Problem Reporter
  26 MB SystemUIServer
Virtual Memory Information: ℹ️
  10.57 GB Free RAM
  882 MB Active RAM
  426 MB Inactive RAM
  740 MB Wired RAM
  414 MB Page-ins
  0 B Page-outs
Diagnostics Information: ℹ️
  Dec 30, 2014, 06:03:51 PM /Users/[redacted]/Library/Logs/DiagnosticReports/WebProcess_2014-12-30-180351_[ redacted].crash
  Dec 30, 2014, 11:00:28 AM Self test - passed
  Dec 28, 2014, 10:43:39 AM /Users/[redacted]/Library/Logs/DiagnosticReports/WebProcess_2014-12-28-104339_[ redacted].crash
AND here is what I am guessing is the relevant info from the report that was sent to Apple:
Crashed Thread:  0  Dispatch queue: com.apple.main-thread
Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: EXC_I386_GPFLT
Application Specific Information:
Bundle controller class:
BrowserBundleController
Process Model:
Single Web Process
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   com.apple.WebCore             0x000000010dd4b48e WebCore::SharedBuffer::createPurgeableBuffer() const + 14
1   com.apple.WebCore             0x000000010dd1fd0e WebCore::CachedResource::makePurgeable(bool) + 62
2   com.apple.WebCore             0x000000010dc201df WebCore::ThreadTimers::sharedTimerFiredInternal() + 175
3   com.apple.WebCore             0x000000010dc200f4 WebCore::timerFired(__CFRunLoopTimer*, void*) + 20
4   com.apple.CoreFoundation       0x00007fff921c9804 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
5   com.apple.CoreFoundation       0x00007fff921c931d __CFRunLoopDoTimer + 557
6   com.apple.CoreFoundation       0x00007fff921aead9 __CFRunLoopRun + 1529
7   com.apple.CoreFoundation       0x00007fff921ae0e2 CFRunLoopRunSpecific + 290
8   com.apple.HIToolbox           0x00007fff931baeb4 RunCurrentEventLoopInMode + 209
9   com.apple.HIToolbox           0x00007fff931bac52 ReceiveNextEventCommon + 356
10  com.apple.HIToolbox           0x00007fff931baae3 BlockUntilNextEventMatchingListInMode + 62
11  com.apple.AppKit               0x00007fff8ce40533 _DPSNextEvent + 685
12  com.apple.AppKit               0x00007fff8ce3fdf2 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 128
13  com.apple.AppKit               0x00007fff8ce371a3 -[NSApplication run] + 517
14  com.apple.WebKit               0x000000010ce437d1 int WebKit::ChildProcessMain<WebKit::WebProcess, WebKit::WebContentProcessMainDelegate>(int, char**) + 387
15  com.apple.WebProcess           0x000000010ccafd4f 0x10ccaf000 + 3407
16  libdyld.dylib                 0x00007fff962987e1 start + 1
Wish I knew what the problem is.