Business hours.  In Russia, work generally starts between 9 and 10 am and wraps up around 7 pm, so this is when most people can be expected to respond to business-related phone calls and text messages. Afterhours has to be an emergency, a previously-agreed conversation or a relationship where you've seen each other without makeup.

Texts and messengers. The consensus here is that contacting someone by essentially a text is a polite way to engage, giving the respondent time to think. It drives my parents crazy, whose reasoning is “Why can’t you just call?” It’s polite to respond within 24 hours. WhatsApp and Viber are popular messengers for work and for friends, but plenty of conversations also happen through Telegram and Vkontakte.

Voice messages. Most of my Russian friends prefer text messages and leave voice messages for when they can’t explain something in 10 words, or it's your boss and they’re driving. Text messages are easier to read, are more searchable and don’t force anyone to listen to them in a crowded metro. Voice messages are especially frowned upon in group chats. Besides, you look like Agent Cooper in Twin Peaks when you record them.

Emoji. There’s a certain art to emojis - describing emotions with pictograms. Experts suggest not to use emojis in conversations with business associates until they do it first, and then limit their use to tasteful illustrations, not a novel in pictures. Inappropriate and offensive emojis are well, inappropriate, not funny.

Word of caution. Keep in mind that any kind of recorded communication - be it a picture, a voice message or a text with emojis - can be saved and forwarded. My personal rule of thumb is not to send anything that could eventually circle back to my boss, my spouse or my mom.