Stride (previously HipChat) vs Telegram

You can access HipChat from pretty much every common platform. HipChat even allows chatting via SMS.

You can ping people to get their attention even if they are not online by @mentioning them. Depending on how the person has set their account up it can be by notifications via in-app sounds, visual alerts, and even email, SMS, or mobile app push notifications.

Including Asana, Github, Zendesk, WordPress, MongoDB, TeamCity, JIRA, Confluence, PowerShell and more that 40 others.

Free with unlimited users, $2/user/month for voice + video calls, screencasts, full history retention and management. (Even enterprise feature like SAML)

An intuitive, easy to overview interface listing both online and offline users.

Things like photos get automatically embedded in the chat thread once you upload them.

You can invite people to join conversations even if they don't have a HipChat account. HipChat will generate a link to share and the guest will only need to enter their name to join the conversation.

HipChat has an optional desktop client powered by Adobe AIR.

HipChat audio and video works on mobile platforms and web browsers.

Participate and keep tabs on ongoing discussions on particular topics or amongst certain groups of people.

If you are worried about third-parties getting access to your data you should consider self-hosting. With self-hosting you are in control over where your data is stored, who has access to it. You will also not be vulnerable to exploits of a third-party provider.

Pasted code can be colored based on syntax.

A big company with experience will bring in more options like Google Apps One Time Login.

E.g. part, away, all, here etc.

Copy/paste videos, gifs, images, geolocation, documents, and even executable files. Drag over files for practically any time up to 2GB in size. Images can be compressed, too.

The application is available free of cost.

In addition to the end-to-end encryption [only in secret chats] that provides privacy to communications, the app also includes self destructing timers for chats, and the ability to permanently delete messages, yours and theirs, from your and their devices.

Videos, gifs, images, geolocation, and documents.

Broadcasting channels suitable for announcing things.

Very customizable with a lot of clean looking options.

In Supergroups, anyone along with admins can delete their messages from all sides. A message can be pinned to the top. All of the user's messages can be deleted by an administrator, and they can be banned and reported as well. Supergroups can have a public link (outside of Asia, due to high spam volumes), which is also a username.

You can set up an additional password to your account, which can be reset by your email. You don't have to use an email if you do not want to. If you lose access to your email or forget your password, you will be able to reset it via text message if your account is over seven days old and will receive it within a week (in case you recover anything before then).

Telegram uses an open source MTProto encryption protocol that provides complete end-to-end encryption for secret chats. To show off their confidence in the protocol the company behind Telegram has organized $200,000 and $300,000 challenges to break the encryption. So far there have been no winners.

You can write messages to yourself. You can write some notes, add links, and see everything across all your devices.

Even though encryption used for cloud-based storage (e.g. Gmail, Facebook, iCloud) may not be as secure as end-to-end encryption or zero-knowledge storage, Telegram does the most that it can by holding keys to chats in different jurisdictions, requiring intergovernmental cooperation to obtain the keys. This is aside from whatever other security measures have been taken, of course.

There are native desktop, mobile and web client apps, that are optimized for speed and are light on memory usage.

Client apps are open source, making whole service more trustworthy.

Unlimited number of files can be stored forever on the cloud. You can upload files up to 1.5 GB each.

You can post voice and video messages if you are too lazy to write text messages.

This Discord-like feature adds to the interactivity of the application.

You can pin messages to the top of groups or supergroups so members will see them when opening the group.

Messages in individual chats can be set to self destruct on a timer. They will disappear after the timer expires.
Messages in all new chats can be set to self-destruct with a global auto-delete timer in Settings > Privacy and Security > Auto-Delete Messages.

Unfortunately, on the desktop videos don't play, but images are viewable without visiting popular websites like imgur and Instagram.

You can play YouTube videos and others within the app, so you don't need to embed code or anything.

With inline bots, such as @gif, @pic/bing, @vid/YouTube, etc, you can look things up without leaving the client or chat that you're in. Simply type the name and some keywords and wait for the results to load.

You can ping people to get their attention by @mentioning them.

The desktop app has a built in setting to scale the UI of the app up to 200% which allows for those with 4k monitors/screens to use the app without scaling issues.

Uses the latest GPL audio codecs, such as Opus, an adaptative high-quality codec that supersedes AAC at any bitrate.

Although it's volunteer based, but still pretty top-notch if available, which it tends to be.

Topics are now available in groups of 100+ members and have a sleek two-column layout and new buttons to quickly navigate.

A default topic called General is now in every topic group, holding the group’s service messages and previous message history.

On SimilarWeb you can see that Telegram is on the top 15 among all communication apps.