Internet Addiction

Nowadays, the internet is the most important way to communicate with the world. The types of relationships types[1] have changed with respect to [2] several years ago. Today, the internet is the first and principal marketing and business tool used by companies. Moreover [3], it is the biggest brochure that we couldn't even imagine.

However, everything has a negative face [4], a dark side. Consequently, the internet too.
Despite all numbered the enumerated [5] positive reasons, there are a lot of reasons by which why the internet isn't perfect.

One of them is internet addiction. As I had said earlier [6], now we don't understand a relationship or friendship without the internet [7]. In other words, without social networks. Therefore, you don't have friends if you don't have whatsapp or facebook. To put it simply, you be are no more (you don't exist)

As a result, we are continuously looking for new messages: we are always searching information about our contacts, we are always reading or typing. It is then, in at this moment, when internet addiction is starting, is when we forget that, there -- just where you are -- [8]there are people.

1. This is more of a usage correction. We don't really say "relationship types", but instead, "types of relations/relationships".

2. "With respect to" is a set phrase.

3. "Moreover" is one-word preface.

4. Other idioms: "Everything has a downside / caveat / price."

5. Or "despite all the aforementioned..."

6. Or "as I had previously stated..."

7. Or do you mean, "we don't recognize a relationship or friendship outside the context of the internet"?

8. These should be emdashes, but since the editing tools don't have this functionality, it can be represented by two dashes.

Great job, mostly just punctuation errors and some prepositions that needed to be changed.

Internet addiction

Nowadays, the internet is the most important way to communicate with the world, The relationship types (types of relationships)/(relationships)have changed respect (not needed) several years ago. Today, the internet is the first and principal marketing and business tool used by companies, more over, it is the biggest brochure that we couldn't even imagine.

However everything has a negative face, a dark side. Consequently, the internet too.
Despite all numbered positive reasons, there are a lot of reasons by which (why) the internet isn't perfect.

One of them is internet addiction. As I said, now we don't understand a relationship or friendship without internet, in other words, without social networks. Therefore you don't have friends if you don't have whatsapp or facebook, simply you be (are) no more (you don't exist)

As a result, we are continuously looking for new messages, we are always searching information about our contacts, we are always reading or typing. Then, in this moment, when internet addiction is starting, is when we forget that, there, just where you are, there are people.

Repeating "We are" in the same sentence is redundant and it's a run-on sentence. Otherwise, it was really good. There were only a few grammar mistakes.