After 18 months of aggressive crawling, MSN is not indexing very deep on large sites, judging from their beta.search.msn.com
This has been verified on four different large sites. A large site is one where Google or Yahoo report over 50,000 pages using the site:www.?.com command.
The counts in Google and Yahoo for large numbers are incredibly inflated using this command. They can easily be double the actual number of total pages on that site. On my own large site, the numbers are four times higher than the total number of pages on the site.
Therefore, you have to confirm your counts by adding another word to the command, as in site:www.?.com extraword
Choose a word that will bring the count down under 1,000. Counts under 1,000 are still inaccurate, but can be improved with this technique:
1) Set your preferences to 100 per page.
2) Click on the last page.
3) Scroll to the bottom. If there is a message that you can repeat the search with the omitted results included, then click on it.
4) Click on the last page and get the actual count of displayed links.
Here are the counts for site:www.webmasterworld.com:
And now with the extra word to bring the count under 1,000, here are the counts for site:www.webmasterworld.com everyman:
After studying why the MSN counts are so low on large sites, it appears that the more your extra word tends to appear on deeper pages, the lower MSN's coverage of that site for that extra word.
In other words, on large sites the MSN crawler has been going deep for 18 months, but the beta.search.msn.com engine is not displaying deep pages on these sites.
Unless Microsoft gets it together, their search engine will not be competitive.