spam - legit emails in junkbox

Hey this is actually a reverse question.
My personal email (firstname.lasname@gmail.com) is winding up in many peoples junkbox and I have no idea why.

What may the cause be? Is it because it has the word Entrepreneur (and programmer) in my sig? is it because my first name is unique(european like)?

Its driving me crazy. I sent out dozens of business emails a month to people I just meet so its actually hurting me much more then others :(

-edit-

I also want to mention this is non spam. Typically I email people I meet and say hi or to follow up. I was requested by someone to send him an email so I can test something, so I did and he replied to me 10 days later telling me he found it in his junk, like many others have said to me.

-edit-

bortzmeyer suggested emailing check-auth@verifier.port25.com I did and here are the results

SPF check:          pass
DomainKeys check:   pass
DKIM check:         pass
Sender-ID check:    pass

SpamAssassin check: ham

----------------------------------------------------------
SpamAssassin check details:
----------------------------------------------------------
SpamAssassin v3.2.5 (2008-06-10)

Result:         ham  (-2.6 points, 5.0 required)

 pts rule name              description

---- ---------------------- --------------------------------------------------
-0.0 SPF_PASS               SPF: sender matches SPF record
-2.6 BAYES_00               BODY: Bayesian spam probability is 0 to 1%
                           [score: 0.0000]
 0.0 HTML_MESSAGE           BODY: HTML included in message