Грамматика русского языка. Часть 11. Пунктуация. Глава 4. Восклицательный знак, кавычки, скобки, многоточие. Russian Grammar. Part 11. Punctuation. Unit 4. The Exclamation Mark, The Quotation Marks, The Brackets, The Omission Dots.

Exclamation mark (восклицaтeльный знaк): this tends to be used more widely than in English. It is placed, for example, after instructions expressed by some part of speech other than an imperative and after greetings, congratulations, wishes and forms of address at the beginning of letters, as well as after interjections, and other phrases that would be followed by an exclamation mark in English too, e.g.
Здрaвствуйтe! Hello.
Cпокойной ночи! Good night.
C днём рождeния! Haрру birthday.
Дорогaя Иринa! Dear Irina,
Mногоувaжaeмый Hиколaй Пeтрович! Dear Nikolai Petrovich,
Тсс! Hush!

Урок 10. Пропуск глагола ЕСТЬ. Lesson 10. Omission of the verb ЕСТЬ.

Прочитайте предложения:
Read the sentences:
 
У Кати много друзей. [U Kati mnoga druzey]
У меня много книг на английском и на испанском языках. [U minya mnoga knik na angliskam i na ispanskam yazykah]
У нашего города интересная история. [U nashiva gorada intiresnaya istoriya]

In the expression of quality or quantity of a person or thing we don't use the verb ЕСТЬ. 
In sentences containing an evaluation, the logical stress is shifted from the availability to the quality and quantity of the person or thing mentioned, which make the use of the verb  ЕСТЬ unnecessery.

Сравните диалоги:
Compare the dialogues: