link:www.act4u.com shows no results and yet there are many inbound links... why?

Greetings, mcjim!

While Google is pretty protective of the algorithms they use to
determine Page Rank as well as the other aspects of their Search
Engine, questions like this are the subject of much research and
speculation by webmasters.

Because of Google's secrecy, it is not known for absolute certain, but
the general consensus among webmasters is that Google only indexes
backward links for a page if IT has a Page Rank higher than 3, and
only indexes the backward links that are coming FROM pages with a Rank
higher than 3.

From Senior Forum Member "Beachboy" at WebmasterWorld:
"Your index page is PR3, Google won't show any inbound links unless
the page you're doing the query on is PR4 or greater."
http://www.webmasterworld.com/forum3/4784.htm?highlight=inbound+links+higher

From Senior Forum Member "Birdman" at WebmasterWorld:
"It is thought that Google only shows backlinks from pages that have a
pr4 or higher."
http://www.webmasterworld.com/forum3/7309.htm?highlight=inbound+links+higher

So, in order to improve your own Page Rank and get Google to index the
backward links to your site, you want to try to get other sites with a
Page Rank of 4 or higher to link to your site.

WebmasterWorld is a great resource for information regarding ranking
and placement in search results for Google and other Search Engines.
http://www.webmasterworld.com

Search Strategy on WebmasterWorld
inbound links higher

I hope that this Answer has provided you with exactly the information
you needed!

Regards,

aceresearcher

I believe Google only shows inbound links from pages that have a high PageRank

You can check out this link which gives the official explanation of
Google's PageRank Technology.

Page Rank Explained!
://www.google.com/technology/

Warm Regards,
Shiv Reddy