ThomE,
No problem. My pictures are somewhat deceiving because the algae is not far along. It does seem though to be the beginnings of BBA -- it's not threads, but little black marks, like pieces of ash. What gives it away is as BBA is its preference for growing along the leave edges (like a fringe), on the surface of leaves, and the color, black.
I have some green spot algae as well, which is more green and circular. Here's another picture of BBA (NOT from my tank), but some of my worse-off Tenellus leaves had progressed to about 70% of this point:
There's some other pictures and other good info here:
http://www.plantgeek.net/article_viewer.php?id=9