Alright, here we go....
A collection of free online SEO / SEM tools
ready to be BOOKMARK !!
Search Engine Analytics
Simply just enter any Url into the search query and voila you get a trend report from link popularity, PageRank™, Alexa Rank, keywords.
This tool will check any web page's header tags.
Search Combination Tool
This tool will generate all possible combinations of two separate lists of search phrases.
Keyword Density Analysis Tool
Enter a page URL and this tool will tell you the keyword density of all the phrases on the page.
Wonder how your page is viewed by a search engine spider / bot ?
Check and benchmark your website indexation against your competition
Find out for which keywords your site ranks high enough to be in Google Top 20. Registering for a free account at SeoDigger gives you information per entire domain as well as per separate pages.
Site Comparison Analysis
A useful tool in benchmarking your website against a competitor via a radar diagram.
A firefox plugin in finding out how well your site fare against the competition in Google, Yahoo, and MSN/Live.
SEO Site Audit Tool
A quick audit on your website or competitor on how well your website is faring on search engines, social bookmarking, etc
SEO Audit Report
Free SEO audit which provides score that incorporates things like website traffic, SEO, social popularity and other technical factors on how your website can be improved from a marketing perspective.
Find out all the important information about your competitor's links. This free tool reporting includes pagerank, anchor texts, no-follow information , etc.
Another tool in digging out everything regarding a website
The free keyword tool from Google
Find out how competitive your particular keyword is / are; Crawl your own website to determine which keyword / s are getting higher traffic
The free Traffic Estimator tool from Google
Get quick traffic estimates for keywords for your sem campaigns
Keyword Competition Tool
Find out how competitive the particular keyword /s is for your sem campaigns.
Search for topics relevant to your search query
Landing Page Optimization Tools:
Loading Speed of your website
How long does your website load in various web browsers ?
Website Speed Test
Another tool in testing your web site loading speed
Page Size Calculator
Useful in calculating the size of your web page and the estimated time it would take to download on a 56k Modem.
Identify how people view your website, photo or ad and which areas are getting most of the attention.
If you know of any SEO / SEM tools that were not mentioned here or missed any goodies, drop a note and I will update the post.
Alright, here we go....