Hey, we apologize for the temporarily downtime - it was due to the upgrading of our hosting today to a stronger server.
Hi, first of all I want to thank you for being a loyal customer. Since we started, the amount of keywords we have needed to check per hour has grown from 2000 to almost 20000. We have been working very hard from working on new upgrades and features to increasing our server capacity to satisfy all of our customer needs. Although there has been some bumps along the way, we will have everything fixed within the next week or so.
As for the night time problem, this is because SerpBook updates its BackLinks, PageRank, Yahoo, and Bing at 12am EST increasing the server load.
We've just increased the strength of our server once again and this should eliminate some of the downtime.
I'll send you a PM regarding your ranking error and we'll resolve it together.
Thanks,
Lanbo