Stride (previously HipChat) vs Chatwee

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.

A bit less options available but works nonetheless.

Including YouTube videos and pictures preview in the chat window.

Chat size, color, fonts, language, log in methods, notifications, emojis, privacy, powerful moderation and many more.

Users, who log in to the site, are automatically logged in to the chat.

Developers provide easy to follow, clear plugin installation instructions.

Chatwee has a clean and easy to use UI. On the left there's a clean and defined user list, each name has a flag next to it. It's also very easy to move from one side of the screen to the other. There's only the most useful information on the screen at any time and the design never feel overwhelming or cluttered.