When someone sends me mail, I look at a few things...
The letter to see how literate the person is or perhaps which country they hail from. The content of the letter tells me if in fact this person took the time to read my profile. You could say I score them for paying attention. If someone sends me marriage proposals and requests I talk to them on IM (YOU KNOW WHO YOU ARE), I ignore the little gnat. I mean, how hard is it to read on my profile that I have NOT got marriage as my listed objective(in fact it says friends) and that my IM is private(feel free to go peek, lol). If they make any kind of comment that is in fact not related to my profile, I refuse any further contact. Ie., "love your blue eyes"... oh puleeez, they're hazel Einstein.
I look at the person's profile. If they say they are from two totally different places... ie.,
"I am from Nigeria" but profile says New York...*errrrt... no deal.
If they try to convince me of something, yet the profile details oppose their comments... denied.
I do check to see if this person even viewed my profile.
I also read to see if they've posted anything in the forums... and yes, I will read back as far as a year. It's amazing what you can catch if you pay attention.
If I suspect something fishy, I google.
Always do your homework. You may not be just helping yourself... but others as well.