If you have seen WhatsApp you will know what XMPP looks like and how it works on a mobile phone, since WhatsApp is basically XMPP (but without the ability to chat with people who are not locked in to it)
Features
There are a number of features which distinguish XMPP from other Instant Messaging options.
Choice of clients and platforms
XMPP is not restricted to Smartphones. There are clients for desktops, and others which can be accessed via a web browsers. Gajim is a good choice for desktops, being available for Linux, Windows and MacOS, so if you use, say Windows, but have a more technical friend who uses Linux, they can still help you.
A good choice for Android users is Conversations, or if you are connected with a UK charity – or are happy to pay a small hosting fee, then Snikket is worth considering.
Multiple Accounts for different uses
Some chat systems are ‘flat’ – using a phone number as identifier. This can increase the risk of accidentally adding an unintended person to a chat.
XMPP Clients will generally connect to more than one account at a time, thus someone who is a teacher, a voluntary fireman and a scout leader could have three accounts, one for each role, but all can be enabled simultaneously.
Note that there are mobile phone providers who do offer an XMPP service, for those who might want a chat address not clearly connected with some organisation. There are also XMPP providers, such as Quicksy, which use your phone number as your account name.
Small actionable steps
XMPP.org – the standards body for the XMPP, has instructions on getting started, which include suggestions for clients to use, and free service providers to try. There is a risk with free service providers, as with anything provided without payment to anyone who asks, that either the person or organisation who is paying for it will run out of money, or they will be using it to promote some premium version, or to gather personal information. Alternative their generosity may be exploited by bad people, who will use it to ‘spam’ damaging the reputation of the service.
End users
If you are a student you inquire to see if you can have an XMPP chat account through your institution, or, if employed, through your employer. If have a connection to a charity you could try to establish if they can offer chat accounts – see below
UK charities
UK charities can apply for a donation to set up their own XMPP server, and described here.
Enhance
If you are a software developer, or sponsor developers (such as Google Summer of Code or Outreachy), there are areas of work which would improve Internet Chat for everyone.
Thunderbird support for OMEMO
Thunderbird is a great mail client, particularly as it runs on Windows and MacOs, as well as Linux and Android. It is also an XMPP client, but unfortunately it is one of the few XMPP clients which does not support OMEMO encryption. As most chats are encrypted by default this bars people using Thunderbird from participating.
There is an open Thunderbird bug for this at https://bugzilla.mozilla.org/show_bug.cgi?id=1237416