What's this stuff?

[Rick Maday]

Jelly, jelly everywhere?

[Larry D. Kage]

Yes, that is SPF jelly.

[Michael Larson]

Sap. Douglas fir.

Douglas-fir is a resinous wood, with a characteristic sweetish odor.. Exudations
of resin on end and side surfaces and pitch pockets are common.

[Bob Elliott]

Yep see it in most attics.(looks like basement here)
The unventilated ones seem to have more.

I notice they are using beam jacks,and do not see any fasteners either.

[Peter C. Russell]

We call them pitch pockets aroud here.

[Martin A. Jorgensen]

Its just pitch.