Is there a way to comment a key locally?

[fmv1992 at gmail.com]

Is there a way to comment a key locally?

Examples:

Let's say I met a guy and we exchanged keys. After 10 years I decide to
send him an encrypted email. How would I remember the guy - key link?
I'm thinking of adding an alias like 'red haired funny tall guy from XYZ
meeting'

Other scenario: I downloaded and verified a file on the internet. For
some reasons I decide to trust that his key belong to this developer.
I will not be using his key for some time. So again when I decide to
download again that software how can I remember that GOOD SIGNAURE from
abc at def is from the same developer?

-- 
Felipe Martins Vieira
Public PGP key: http://pgp.surfnet.nl
Key Fingerprint: 9640 F192 63DA D637 6750 AC08 7BCA 19BB 0E69 E45D