Every year our fig tree is covered in figs. They grow in size but never mature into edible fruit ie the inside is hollow with immature seeds.
http://apps.rhs.org.uk/advicesearch/profile.aspx?pid=106 has advice on cropping. Basically you need to remove any overwintering fruit and just leave this year's fruits.
A fascinating problem. Is your fig tree a named variety or a self sown seedling? It would appear that there are different types of common fig, some of which have only female flowers and are self fertile and some of which have male and female flowers and need to be pollinated by an almost microscopic fig wasp. It may be that you have one of the latter and that the figs you see are unfertilised and therefore immature fruits that are waiting for this little wasp to come along, burrow into the "blossom" end of the fruit, lay her even more microscopic eggs and leave, having pollinated the fruit on her way. The eggs hatch after several weeks inside the figs and the new generation of little wasps fly off to start the whole thing again.
More on Wikipedia!
In the autumn you need to remove every small fig that will not grow to maturity that year. The figs that will develop the next year go into the winter in the topmost leaf axils about the size of a small pea. Really very small indeed. Take a good look at the end of the branches when the leaves drop.
The trouble is that fig trees have two harvests in warmer countries. In the UK they only have one out of doors as they are really on the edge of their range.
Luckily in this country figs do not need to be pollinated, which makes home-grown figs so luscious - no seeds!