europeforvisitors - 6:27 pm on May 5, 2006 (gmt 0)

But the question is, if it is too late to start some new sites on specific high payed AdSense keywords and try to earn some money?

Probably. There have been lots of changes in the program since it began:

1) Advertisers now have blocking filters;

2) "Smart pricing" reduces earnings of publishers who go for easy money at the expense of advertisers;

3) Advertisers can now bid separately for the content network (unlike in the beginning, when one bid covered everything, there were no "smart pricing" discounts, and many advertisers didn't realize that they'd be included in the content network unless they opted out).

Also, the search engines (or at least Google) have become more wary of get-rich-quick, made-for-AdSense sites: which is why members here seldom talk of scrapers these days, but instead complain about "MFA" sites that use PPC arbitrage as a way to earn money.

I know that the "golden" days are over and that is now much harder to earn serious money. So answer please realistic. I would like to earn about 200-400$ a month.

I wouldn't call $200-400 month "serious money," but it represents a nice second income for many people. It shouldn't be too hard to make $200-400 month with a smallish but genuinely useful site on the right topic, though it won't happen overnight.