how close has the L$ to the US$?

What is the closest the linden dollar has gotten to matching (or beating) the US$ and what is the influence for the value of the L$, if the L$ ever had potential for 1 L$ to the US$ would Linden Labs prevent it?

For a good while it was around 1:160, but there were some pretty nasty situations which lead up to that. (Lots of wholesale extortion by the land barons of the time - since the supply of land at the time was very limited prices were absurd - L$20/m and up. LL then started releasing lots and sunk it to it's present value - now land is an on-demand thing which means those prices are unlikely to happen ever again.)

i am sorry i am familier with the words, just not when they are strung together, could you dumb it down for me?

Around ~$6.00 per L$1000 is the answer to your previous question.

The reasons were supply and demand in the land industry; Supply was very limited, so price gouging occured on what was availible; making the average L$ per sqm greater than L$20.00/sqm; this caused lots of people to buy Lindens to purchase land which caused the price to rise with demand to that value.

Now land is cheap, content is the biggest reason people buy L$, but you dont need to buy as much and supply is plentiful so it's unlikely we will see prices like those again.

but it is all virtual what could cause a land shortage?

Land is the one part of SL which isnt virtual - it's basically server time. Every sqm gives you rights to 0.00152587890625% of the servers processor usage.

Servers cost realworld money for:
- Electricity and Cooling
- Storage
- Bandwidth
- Hardware
- Maintainence
etc.

Each sim is a computer. For LL to add land they can't just magically press a button or two to create it. SL currently runs on 1000+ computers. Land tier is what pays for those computers and their maintenance.