If you’ve been using a Mac long enough to rememeber Acta, this is the moment you’ve been waiting for. Acta was one of the original outliners, right up there alongside MORE as one of the most popular and well-loved applications of its kind back in the Classic OS days. (See Robert C. Eckhardt’s 1987 article Inside Outliners for a guided tour of what was hot at the time…)

And it hasn’t died. People have continued to use it in Classic mode - at least, they did until the switch to Intel. When that was announced, Acta’s creators at A Sharp software decided that the time had come for something new.

Opal is the result. It’s a Universal Binary and requires 10.4, but it’s been designed to appeal to long-term Acta users and should, according to A Sharp, “open 20-year-old Acta documents” without a problem. Now that’s legacy support.

Opal is still very much beta, but it feels nice. It’s not a power-outliner like OmniOutliner, but it has a responsive, minimalist feel to it at the moment which is quite appealing. Outliner addicts, give it a whirl. Tell us what you think.