join.me is described as 'Easy to start, easy to join and with no downloads for viewers, connecting for external presentations, sales demos, and ad hoc get-togethers means you get work done and get on with it' and is a well-known app in the Remote Work & Education category. There are more than 100 alternatives to join.me for a variety of platforms, including Windows, Online / Web-based, Mac, iPhone and Android. The best alternative is TeamViewer. It's not free, so if you're looking for a free alternative, you could try Jitsi or Chrome Remote Desktop. Other great apps like join.me are AnyDesk (Free Personal), Zoom (Freemium), DWService (Free, Open Source) and UltraVNC (Free, Open Source).
Jitsi (previously SIP Communicator) is an audio/video and chat communicator with full encryption that supports protocols such as SIP, XMPP/Jabber, ICQ/AIM, Windows Live, Yahoo!, GTalk/Hangouts extensions, as well as OTR, ZRTP, etc.
DWService is an open source project which offers a service that allows access to remote systems (Windows, Mac, Linux, Raspberry...) using a standard web browser - without any component required on the client side.
UltraVNC is easy to use and free software that can display the screen of another computer (via the Internet or a local network) on your own screen. The program allows you to use your mouse and keyboard to control the other computer remotely.
Support customers on a remote computer easily through web-based, on-demand remote support sessions. Set up unattended remote access and manage remote PCs, laptops, mobile devices, and servers effortlessly.