Googlebot accesses web pages every few seconds, how Google uses this info I don't know. It's a web crawling robot, it detects links on each page and adds them to its list of pages to crawl.
There are ways to prevent Googlebot from following any links on your website. There is also a way to block Google from access to your files and directories of your server using the no follow meta tag.
It's to let sites get more web hits on Google, by sacrificing your members privacy. I don't know if I like that.
Bingbot is by Microsoft, same thing though, don't know why Microsoft needs to be on here, is Microsoft a search engine? Why would they even need this?
Data mining tools is what I see.