A howl is a term from the early days of the werecommunity, meaning a gathering where weres meet in person. Often, a howl takes the form of a group of weres going camping, or sometimes, merely "camping out" at someone's home.
Not all were-gatherings are necessarily called Howls these days. Some people feel it's a wolf-centric term, or have other reasons for calling them something else. Some gatherings, hosted by feline types have been called "meows", in a kind of whimsical response to the term "howl".
While many howls and gatherings were initially open to all weres who wanted to attend, many of them have instituted policies for being invited, in response to some difficulties experienced in the past. The fact that most of our community meets through the internet, more or less anonymously probably made that inevitable. When you hear about a gathering you wish to attend, you'll generally need to contact the organizers to find out what the rules are.
Some howls are still relatively open, while some want to make extra sure they know who is coming first. Howls occur several times a year in the USA, and there are also Howls hosted in Europe, Australia, and other countries.
Attendance at a howl may be as few as four or five people, or, occasionally, as many as thirty. They are generally fairly informal social gatherings.
There are several sites online where people organize howls and other were-gatherings, and where you can get information about attending one or planning one.
A Howl is a gathering of AHWW packmembers, where they... er... howl. These meetings help Weres to get together and be around people who are more understanding and tolerant of animal natures. You can learn more about Howls by visiting the EuroHowl'96 and EuroHowl'97 web pages.
A Howl is a gathering of members from the newsgroup alt.horror.werewolves. At these meetings, pack members interact and enjoy each other's understanding company. There are therianthropic discussions, bonfires, nature walks and just general socialising. Most of the Howls are held in the States, since that's where most of the pack members reside, but occasionally the European pack members get together in what have been named "EuroHowls".
Gathering of Thians and nonthians to meet and play games and make some noise. It varies with the group of people.
A Howl is a gathering of weres, simple as that. Many weres from across the world come together at Howls to share stories and just have fun with others like themselves.