I realize that my compute power power is trivial, BUT why am I processing data 13 years old

You're posting on the BOINC forums, not on the Seti forums.
As for an answer as to why Seti runs older work, they've just released a new application that's capable of looking even deeper into the data than before, so they're rerunning older tapes.

Even then, the data was recorded at a distance of multiple light years away from Earth, so any of the data may have a WOW signal. Seti doesn't do real-time recording, but even data that they would've recorded yesterday will have taken multiple thousands of years to reach the antenna. So do you really think it matters if it's slightly older or not?

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