Two of the web's most popular communication providers, Facebook and Hotmail, have recently updated their services, but the moves have raised questions about the influence of their respective users.

How much power do users have over the design of free web sites that they use for communication purposes? Why do web site redesigns have the potential to create so much user distress? And why do some vendors listen to user redesign feedback more than others?

While Facebook's update caused its users to join petitioning groups on its site against the new design, some amounting to more than 200,000 members, the firm has largely ignored the criticism.

But Microsoft, in response to more than 2,000 complaints about its updated Hotmail look and features, issued a statement promising to investigate the problems and remedy the situation as soon as possible.

Microsoft posted a blog entry listing ways in which it would answer user demands, including the promise of more themes and an increase in the default number of messages users can see per screen.

So, why have these two companies responded so differently to user reactions? IDC analyst Caroline Dangson suggested that one of the main reasons is the nature of the complaints.

Firstly, most of the user complaints to Hotmail were technical and therefore required rectifying, while Facebook users were most concerned with the new layout.

According to the Hotmail postings, users have had trouble accessing folders and emails, and forwarding and replying to messages. Other Hotmail users have complained that the new design does not sit well with their screen size. Microsoft has promised to give inboxes more space to satisfy users with smaller monitors.

But Dangson also pointed out that Hotmail has the potential to lose more business than Facebook from its redesign.

A recent IDC survey found that about a third of Hotmail users also use Yahoo, and 40 per cent also use Gmail. "If Hotmail chose to ignore user feedback, it risks a large number of users jumping ship," she said.

This contrasts with angry Facebook users generally staying put and, importantly, increasing interaction with the site by joining Facebook groups.