Why do I loose visits at the beginning of the month?

[runner07]

My non-commercial video-art website has been online for a year now.
Up to last february the number of visits used to increase regularly. In that period I used to have about 80 visits a day: 40 users were real users and other 40 were crawlers.
Since the beginning of last march the visits began to decrease, mainly during the first two weeks of the month.
Either the number of users or crawlers decrease at the beginning of the month and, in particoular, US commercial users disappear.
I have optimized the tag meta-name, title and metadescription.
I have optimized the use of the tag h1, h2...
I have a good position on search-engines from which, infact, I get visits.
But the number of visits is always dicreasing at the beginning of the first two weeks of each month.
Anybody knows why this happens?
V.S.

[specter]

Hi,

Have you checked your position in the SERP?

Are you sure you aren't loosing positions?

[runner07]

I'm listed in SERP exactly as I want and I dind't expected so much. My position in SERP are really good on yahoo, AltavistA and msn, not that good on Google.
I'm sure that I'm not loosing position on search-engine.
Thank you for your answer.

[monkeythumpa]

Maybe your visitors need to pay rent and don't have the time goofing off watching your videos.

[runner07]

yes, may be.Thank you.
Two days ago I had 176 visits,
150 visits were from crawlers, the other were from users
and the most of the users became from search-engines.
Yesterday I had 26 visits, 15 were users and the others were crawlers.
Yesterday I have noticed that "KBytes per Day" of my site has been more or less at the same level in the past 4 months,: 12000 bites each day.
May be that it means that the number of the real users
-not the number of crawlers- has been costante in the last months.
Ciao