hi Opu
sorry i've been away for a while also.
i'm approaching 2000 active users now, with about 150 - 200 inactive acounts waiting to be deleted.
To deal with the issues i've split up my users into different subdomains, limiting each one to 1000 users which i've found to be able to handle things ok, apart from the page impressions, as you say, users who have a lot of page impressions have a lot of blank spaces. I have not had any problems with referrers.
i had a japanese porn site sign up who sent me 300,000 data packets a day

pphlogger really didn't like that haha
there aren't many non opensource which compare to pphlogger, i've researched many of them and decided i want to invest in improving pphlogger. It's code is old now, based on php3, it needs updating to improve speed and stability, and i have a good few ideas for new features, which i'm sure you also do.
I'm also prepared to pay around $300 , well i did have dollars in mind but i'm sure i could stretch to match that in euros.
opu i will pm you, i'm sure i saw someone else interested in investing in a new version.