The Mozilla browser recently reached version 1.5 - another significant step in its evolution away from the primordial software-soup from which it sprang. Version 1.0, which shipped in June 2002, took four years to coalesce from the Precambrian code donated by AOL's Netscape arm.

The most promising offspring of Netscape is not Mozilla itself, however, but its Firebird sibling. Still in a pre-release 0.7 version, Firebird is already an impressive beast. It is more stable, in my experience, than the shipping version of Internet Explorer 5.5.

The goals of the Firebird team are simple and admirable: to create a truly useful and useable browser. In their own words that means software "without the constraints of commercial interest and the creep of esoteric features from the developer community". Or, as the Firebird charter goes on to say, "The goal is not to have more or less features than any other client but to have the right set of features to let people get their jobs done."

I love the mission statement and I like the product too - I've been using Firebird for about three months. The rough edges are still apparent - there's no installer, it doesn't support DHTML, it systematically mixes up the little square "favicon" images served up by sites, plug-ins have to be manually loaded, and some of the entities in the options box are little more than developer notes.

But on the plus side it hardly ever crashes. It feels fast. It's more flexible and simpler to customise than IE. Its tab system works wonderfully.

And it offers a way to manage stored passwords - a dangerous omission from IE. A host of add-on features can be loaded and, most importantly, it blocks pop-ups.

The most frustrating aspect of using Firebird is not of the browser's own making, however. Using it offers a lesson in browser bigotry among web site owners.

The worst offender I've discovered so far belongs to health club chain Holmes Place. The company's site greets users of Firebird with a virtual brick wall that says "We're sorry. Your browser is not able to access the Holmes Place web site". It goes on to say that the site "was developed for Microsoft Internet Explorer versions 5+ and Netscape Navigator versions 6+ browsers, on PC and Macintosh platforms". And that's it - no lite site, no content, no nothing.

Of course it does the same thing to users of Mozilla, Opera, Lynx and even Pocket Explorer - and no doubt will give the same two fingers to blind or partially-sighted users of specialist text-to-speech browsers.

As well as being illegal, this is simply not very nice. It's a bit like the same firm proclaiming that its exercise machines only work with the latest Nike or Reebok trainers, and that wearers of other brands or older footwear should switch shoes or sling their hook.

As is often the case with such sites, the frustratingly unobtainable interior offers no special reward. There is nothing on the Holmes Place site that Firebird can't handle.

Firms like Holmes Place need to realise that the web does not belong to Microsoft and AOL.

Firebird is due to reach version 1.0 next summer, and it deserves a decent chunk of the market. However, even if Firebird remains a curiosity, site owners should accept that barring novel browsers is a narrow-minded move that can only be bad for business.