Grammar, Usage / The apastrophe question and more [2]

I am so sorry but I found more and this is due tomorrow.

Michael reiterates Williams' (is the apastrophe in the correct spot?)main priority of customer satsifaction; Therefore, as the compnay began to popularize, all changes were made based on the customer...(Semicolon, capitalization of therefore, and the commas. right or wrong?)

There was no other company like Ebay; therefore, the company had the freedom to try new things and not worry about competitors too early after the company began. But as more e-commerce websites began to appear at the end of the 1990's, the company had to fight to for its brand name and special features.

The semicolon and comma, I do not know if they belong there.Also the period before the 'but.'Something needs to be there but I do not know what.

Ebay has shocked many with the magnitude of its' success. Unlike many of its' e-commerce counterparts today...(should the comma be there and if so before or after the 's'

this is it I swear. Thank you so much!

Grammar, Usage / newfound, vocab... grammar... and more! [2]

I have a few more bits from my essay with some words in bold that sound odd. I need help fixing them.

Ebay's newfound recognition (All the sudden the compnay was in the spotlight and everyone was paying attention to every move they made)

Though the internet had been around for a while it gained a public face in the 1990's (Should there be a comma between while and it.The internet had been around for decades but in the 90's it became very well known to the world.)

Many businesses sought to reach a wider variety of customers. (This sounds terrible)

The company began to thrive "what is a better way to say thrive?)

Do commas appear before 'but?' EX. Most of the events described in Jon's life seem irrelevant to Ebay but as Willamson continues to describe who Jon Lang is...( and theres a lot more after this)

Grammar, Usage / new heights; grammar, sentence structure, AND vocab! [2]

I am having trouble with the things in bold and I have no clue how to fix them.Please help.

As the company reached new heights (The company was becoming very popular so they reached a 'new height.'What is a better way to say this?

All changes were made based on how they would affect the customer. (Affect or effect?I know, I should know this!)

Many of the employees were highly educated and well experienced people, such as Harvard graduates of former Wal-Mart corporate managers. (this sounds a bit odd)

Michael analyzes the likelyhood of the compnay succeeding (likelyhood, just need a different word)

Every mistake and achievement was highlighted by the media. (Better words to use)

When writing about a certain decade( 1990's) is there a problem refering to parts of the decade as the early 1990's and late 1990's? Would the 20th century sound better?

Thanks a bunch!