I have a ton of new pictures in Aperture (from a vacation.) I am trying to figure out the most productive way for me to crank through them and add a comment or new title. What I have seen calls up a dialog box for each image which will take a long time. Thanks
@terrydev's answer is good if you want to set a lot of photos to the same caption/description.
If you want a faster way of entering individual captions, you can use the "Info" inspector panel (default shortcut is Ctrl+D or via menus:
View / Inspector / Info). The drop-down menu at the top lets you choose which set of metadata to display, I think the default "General" one includes caption, version name and headline...
You can type data in any of those, tab between them as usual, and use Cmd+← or Cmd+→ to switch to the previous/next photo in sequence.
This can make it much faster than using the menu + pop-up window for each individual photo. The data will be retained in exported images (if you don't strip metadata on export), and will show up in Facebook/Flickr/etc based on these fields.
Under the Metadata menu note the Batch Change option (Shift+Cmd+b). This allows you to add metadata to batches of photos at once. Note also that you can customise the fields available in the dialogue, so don't panic if the caption field (or whatever) isn't there. At the 'Add Metadata Info' drop down you can edit the preset and choose which fields you require