OSPF and VLANs

Question

Scope of Inquiry:
I've supported heterogeneous networks for merely a decade, but never quite big enough to expose me to Enterprise routing/switching concepts in real-time. I've supported numerous Metro Ethernet hub and spoke topologies, as well as a few racks in a datacenter environment ... however, once again ... no real application of OSPF, EIGRP, etc. 
I'm learning some of the fundamental concepts of OSPF, adjacency, LSA types, etc... but one thing that has me tripped up is whether or not/how VLANs would be leveraged in a real-world scenario, in an OSPF environment.
Can anyone kindly give me a very clear and concise explanation/high-level explanation of the contextual application of VLANs in an OSPF network, including whether or not tags would exist in each area, etc. * Please do not pontificate --- that is to overstate a simple explanation with extraneous details that are outside the scope of a basic/real-world explanation. Hope that wasn't too terse, but I'm trying to gain a working knowledge of the protocol and its nuances quickly. 
Thanks!
-Data-

Answer 1

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Hmm, don't know if I can briefly provide such a description.  Currently, I work in a large company (about 100,000 employees [with about 5,000 Enterprise switches and routers]) and my purview is about 10% of our Enterprise's switches and routers.  My sites range is size from just supporting a few hosts to thousands of hosts, equipment "sizes" range from Cisco 800 series ISRs, up to 6500s in VSS pairs.
From a VLAN standpoint, VLANs generally provide subnets for hosts which also range is size from a /29 up to a /23.  VLAN/subnets are defined principally for like hosts and sized for the number of like hosts.  However, generally like host VLANs/subnets are split into multiple like VLANs/subnets once you get up to about a /24.
A VLAN/subnet might only be hosted on one large chassis (4510 or 6509/6513) or it might be hosted on multiple L2 switches (2Ks/3Ks).  Generally (but not always) VLANs/subnets do not span multiple sites.
At the moment, all sites with a region, generally one or more adjacent US States, are grouped into the same OSPF area.  I.e. such a region might have 50 to a couple of hundred OSPF "routers" in the same area.
Originally area zero was used to tie the region areas together, but currently BGP is used with the WAN core (between regions).
OSPF, per area, of course has all the subnets being hosted by VLANs and also all the (numbered) p2p links (per region/OSPF-area networks can run into a couple of hundred).
LAN designs are generally just 1 or 2 layers, this because you can host so much on a large chassis or stack.  For example, at one of my larger sites, my user edge devices are 3 6509s with 96 port line cards.  As the users ports support both VoIP and data VLANs, a single data or VoIP VLAN spans two line cards (i.e. 192 ports).  So with 7 user line cards, the chassis hosts 4 data VLANs/subnets(/24) and 4 VoIP VLANs/subnets(/24).  As the 6509 has a L3 sup, the 8 chassis subnets are included in that device's OSPF router section and advertized to the rest of the OSPF area (via a dual gig, L3 Etherchannel, uplinked to a site core 6509 - the latter having two 10g SM off-site OSPF p2p fiber links).
At a small (old technology) branch, I might have a "ring" of several 2K series switches.  For routing I'll have some 3K switch with an off-site gig link and a connection to one of the 2K switches.  I might also have a small ISR with a VPN tunnel, for off-site, with a connection to a different 2K switch.  There will be one to several VLANs/subnets defined on the 2K switches and 3K switch.  The ISR will indirectly have access to the VLANs via .q subinterfaces.  The 3K and ISR provide the subnet getways and include the VLAN/subnets into OSPF.  The also generally will run HSRP for the VLAN/subnet gateway IP.
At a small (newer technology) branch, may have a L3 stack and an ISR.  One stack member has the high speed off-site gig link, the ISR connects to a different stack member.  However, the ISR now has a L3 routed p2p link to the L3 stack; there's no HSRP.  Yet, VLANs/subnets are pretty much as the above (paragraph).
Hopefully the above gives you a view into some real world, large scale, with VLANs and OSPF.
If you have additional questions, feel free to ask.