The clue as to what a bridge camera offers is in its name. Bridge models slot inbetween digital compacts and DSLRs by offering the finer points of both genres. This makes them ideal for photographers who like the simplicity of a compact camera, although occasionally find it rather restrictive in terms of lens range and picture taking features, but don't want to make the leap to a full-blown DSLR. The models in this category, then, offer a 'bridge' between the two camps. Clever, eh?!
In most cases, a bridge camera also represents the middle ground in terms of physical size and handling ergonomics. Whereas a compact is largely about sleekness and pocketability, a bridge camera is typically a more sculptured affair with a chunky handgrip, sizeable rear LCD and large buttons that make function setting easier. While you could never describe a bridge camera as large, you'll certainly need to trade up a size or two in bags if you're currently a compact user.
Lenses on bridge cameras are fixed, but offer a whopping zoom range, so it's unlikely that you'll be left wanting when it comes to taking pictures. A typical zoom range will enable you to tackle everything from landscapes at the wide-angle end through to tame wildlife and sporting action at the telephoto end. They also focus reasonably close, so you'll be able to tackle some macro shots too. While having a fixed lens may be seen by some as a disadvantage (if you do, a DSLR is more your bag), it does mean that you'll never have any problems with dust getting on to the sensor and spoiling your shots.
When it comes to features, you'll find that most bridge camera have a foot firmly in the DSLR camp. While they offer the point-and-shoot simplicity of compacts, should you require it, they also have a DSLR-style set of exposure modes, metering patterns and file formats. Buying a bridge camera certainly won't prevent you from shooting using manual exposure, spot metering and the Raw file format should you so desire, such functions just maybe a little more hidden than they would be on a standard DSLR. Similarly, megapixel counts are also more likely to be in double figures, although they're not directly comparable to a DSLR as the sensors are smaller and so won't necessarily deliver the same results.
In most cases, then, a bridge camera can really be viewed as a DSLR with a lens that you can't change and, as such, are a very appealing proposition. Be warned, though, if you really enjoy using your bridge camera and get more involved in your picture taking there will be a time when you'll want to make the leap to a DSLR – this photography lark can be highly addictive!