There are loads of tools and services u can use to diagnose, optimize, enhance and moniter your website here are a few that i use not just becaz they are free but also as they are better than the most free and paid services out there!!!
Use these to make ur site/blog more featured, enhanced and kool!!!
Webstats: www.statcounter.com [ my favorite site counter & site stats service, tested tried so many and finally found this! has loads of options and features, been using it ever since more than a year now and there was nvr a single downtime. ]

Analytics: Google Analytics [ knw which pages are searched and seeked for on ur site improve on topics there is more traffic on optimize ur content and much more… ]
Site Alerts: Msn Alerts [ let ur users know on their mail mobile and messenger what or when ur site is updated. signup and receive alerts all u hav to do is give a signup link on ur site.]
Site Moniters: www.mon.itor.us , www.site24x7.com [ these actually give service thats equalent to paid services of many monitering services] www.vertain.com [ this one has speed tests and speed moniters too, helps in optimizing the site. (suggested by abhi) ]
Feeds: www.feedburner.com [mutate ur feed to a superfeed add features looks and more…]
Source: HTML Compress [ Any content of ur site html js vb you can use this tool to compress and load faster. (actually removes uneeded charector and line space) increase speed of loading decreases loadtime almost by 50% + a lot user friendly just point the directory of ur files it does the rest ]
Translations: Google, Babblefish.
Site Search: MSN (1), Google (blog) [your site needs to be indexed to use these] else use Freefind (bots search and index ur site immediately.)
The services and tools mentioned are suggested for Pro sites if u hav a personal site u can add more features like comments, guestbooks and many more…
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