Zipkin is a tracing system originally created by Twitter and is currently run by the OpenZipkin volunteer organization.
Follow @zipkinproject on Twitter for news including release announcements and community events. You can also ask on gitter about something specific. If you are working on code, you can also follow projects like the server or an instrumentation you use.
OpenZipkin is primarily volunteers, and there are a lot of ways to help. Once you are on gitter, you might notice others asking questions you once asked. A great way to give-back is to help others who are just starting. We are at a number of events, and these are a great way to meet others you collaborate with. You can also host your own Zipkin meetup, similar to how our Tokyo user group started. If you notice something interesting on Twitter, tag it with #zipkin so that others can see it. Last, but not least, you can get involved with the code, docs and project maintenance.
Most OpenZipkin efforts start as localized experiments, then progressively build traction before becoming a feature. Before you start a large effort, be it docs or a test framework or a feature, check with one of the above channels. Someone may already have worked on this in the past and might join your effort. Sometimes, features are intentionally absent, usually with rationale documented in an issue. Regardless, the best advice is to join the community before proposing change, and read one of our HACKING files which explains important aspects of change culture.
Use the plain logo for web sites and for printing. As it is a vector image, it can be scaled without creating pixel artifacts.
It can also be used to print transfer stickers. A minimum size for transfer stickers would be 12.5 cm x 7.42 cm. Smaller sizes might break the delicate design of the logo.
Use the logo with a cut-line for printing kiss-cut stickers. A minimum size for kiss-cut stickers would be 7.5 cm x 4.62 cm. Smaller sizes might give you problems with the inner corners when you want to peel-off the sticker.