The Economist just published an interesting piece called The Geography of Start-Ups, Something in the Air, Why Birds of a Tech Feather Flock Together.
The distilled message of the piece argues that following economic theory, companies of all sizes (esp the small ones) tend to gravitate together due to a variety of reasons: ideas, labor, access to money, proximity of advice…thus a magnetic effect.
In the Valley people are also close to the latest ideas. “Ideas are exposed to that little tiny region possibly years ahead of the rest of the world,” reckons Mr Stoppelman. “You are always building on the idea that came immediately before. If you are trying to build the thing that comes next, early access to information about the things that are out there helps you.”
Does this thinking carry over to the dating game? Absolutely. Eligible people are drawn to vibrant locations that house other like-minded professionals. Condensed metropolitan locations like San Francisco are a great example where one city can sustain itself built on ecosystem after ecosystem of living hubs. For instance, those folks who choose SOMA, compared to Pac Heights or The Mission often flock to a neighborhood that defines them, arguably to be around others like them (and if single to increase the probability at meeting a mate who is near them and like them). In other words, the neighborhood you choose is a direct extension of your personality, right? 
At Linx, we have a lot of clients that are very specific in their requests. An example might be “ideally she’s more of a mission sorta- girl and not Pac Heights” or she says, “it would be preferred if he was comfortable in Russian Hill or the surrounding neighborhoods compared to the Sunset, Dog Patch.” 
Like the start-ups that nest together, single men and women do the exact same thing. Sociographics, demographics all parlay into access to ideas that could be intriguing, proximity to the types of mates they would like to end up with, and I’d say most importantly being comfortable (safe, happy, at ease) in your surrounding. This comfort can become very close-minded when dating- not only wanting a match just like yourself but never leaving your neighborhood because your own ecosystem has everything it needs in it- so why leave and diversify? Can banding together with your “type” of like-minded person potentially harm the dating game? In other words, do you feel broadening your reach is important when casting your dating net?
I‘d love your thoughts on this as well…write me amy@linxdating.com
Linx Line 
When I first moved to San Francisco, I lived in the Marina. I loved it because it was so close to Crissy Field, it was easy to get to work and just generally a good introduction to the city. I found however that when I shared my choice of neighborhood, people who were in more creative, entrepreneurial or tech fields, they assumed I was not very intellectual or interesting. Ironically, after I moved to my current home which is at the edge of Hayes Valley and Lower Haight, I get a completely different reaction from these same individuals. I have to laugh when I think about it because while I am still the same person, I seem to have been shifted to a different SF category type simply based on my geography.