Thanks for the link, Concorde1993!

The photo of the blown "dipped" tantalum capacitor on that riser card is shown here:

http://img201.imageshack.us/img201/917/img1005z.jpg

It was interesting to read TechKnight's opinion here:

viewtopic.php?p=138534#p138534

Interestingly, some capacitor manufacturers disagree that tantalums "age":

http://www.kemet.com/kemet/web/homepage/kfbk3.nsf/vaFeedbackFAQ/6E593B9AE78FE87985256E5B007BAE27

But if we accept that solid tants do age, aging would vary by the type of solid tant (e.g., the thru-hole "dipped" kind vs. the SMD type that trag sells here). (We should exclude wet-slug type tantalum caps here, as they are hardly better than fluid filled electrolytics in terms of longevity.)

And as you may expect, capacitor reliability over time varies by manufacturer:

http://www.electronicspecifier.com/Resistors-and-Capacitors/Low-ESR-high-rel-tantalum-capacitors-minimize-failure-rates-in-long-life-commercial-power-supplies.asp

http://www.avx.com/docs/catalogs/trj.pdf

There's an interesting article on Capacitor Reliability here:

http://my.execpc.com/~endlr/reliability.html

When you open that web page, search for "Solid tantalum capacitors" to skip down to the right part. And if you scroll down even further, you can find a tantalum capacitor life expectancy formula.